Live data from Hacker News

An Interactive Introduction to Fourier Transforms

jezzamon.com

21–23 of 23 posts

Re: An Interactive Introduction to Fourier Transforms

#21

At the time of writing the Gibbs phenomenon -- the overshoot occurring at discontinuities of a square wave, which does not go away no matter how many harmonics are included (see https://en.wikipedia.org/wiki/Gibbs_phenomenon ) -- is not correctly represented in these visualisations, implying that important aspects of the underlying maths are obscured. In my opinion this limits the didactic value of an otherwise impre…

Yes, apologies I made some approximates in the article! Interestingly if you're talking about discrete time fourier transforms (which is what we usually deal with in computers with jpegs, mp3s, etc), then you can perfectly represent a signal with say, 1024 samples using exactly 1024 sine waves without worrying about that effect. It's only in the continuous time variant that you have to worry about things like the Gib…

Right! I did assume a continuous space because that's what it looked like to me. Hence my pedantic comment which was sort of comically at odds with the light-hearted spirit of your article :) Very nice work. Thanks for sharing, and for the clarifying remarks!

Re: An Interactive Introduction to Fourier Transforms

#22

This is incredible. If I wanted to collect things like this to teach my kids, where do I look? How do we gather amazing resources like this in one spot? I particularly love that it focuses on one topic and nails it.

For interactive explanations check out: https://explorabl.es/

Re: An Interactive Introduction to Fourier Transforms

#23

Very cool. One idea that would be cool to see is a repeat of the video where the number of ‘harmonics’ is clipped. Eg, show the video with only the first 5 circle components. Then the first 10, the first 15, and so on. Will see the drawing approach the final image, and get the idea the low-freq harmonics do the bulk of the work but high-freq ones give the small details to make the hand a hand.

This is included in the article. Slide the slider below the animations to control how many circles will be used.
Post reply on HN